Egyptian Journal of Botany http://ejbo.journals.ekb.eg/ 61 D EVERRA tortuosa is a dominant woody perennial shrub (family Apiaceae). It spreads in arid regions characterized by strong climatic changes that affect production of bioactive natural products. In Egypt, it is widespread on the North-Western Coast and Western and Eastern deserts. It is used in folk medicine and as fuelwood by local inhabitants. In the present study, qualitative and quantitative tests were performed to investigate the main chemical constituents (primary and secondary metabolites) of D. tortuosa collected from 17 locations representing seven different habitats. The study also aims to clarify the effect of several environmental conditions on the main biochemical components of the plant. In the present study, D. tortuosa grew in adverse environments, particularly in summer, which improved the production and accumulation of some antioxidant compounds, including tannins, alkaloids, cardiac glycosides, flavonoids, saponins, phenols, carbohydrates, proteins, and lipids. D. tortuosa produced a high content of total carbohydrates (32.18% in salt marshes, which recorded the highest EC,0.54mS/ cm), crude protein (19.88% in sand flats), total alkaloids (111.5mg/g on roadsides, which also recorded the lowest content of organic carbon, 0.16%), total tannins and flavonoids (17.76 and 73.56mg/g, respectively in fig fields, which were characterized by high soil pH, 7.8). Therefore, D. tortuosa shrubs preferred an arid environment and can be considered a new source of several different metabolites that can contribute to drug improvement. In addition, the study provides insight into unusual strategies to increase the efficiency of wild plants for accumulation of phytochemicals.